Embodiments of the present invention relate generally to medical devices and methods and more particularly to minimally invasive devices, systems and methods for treating sinusitis and other ear, nose & throat disorders
The human head includes a number of hollow cavities called paranasal sinuses, which connect to the nasal cavity via small openings called “ostia” (sinugular “ostium”). Generally, the human head includes eight paranasal sinuses (two sets of four on each side), called the frontal, ethmoid, sphenoid and maxillary sinuses. The frontal sinuses are located in the forehead, the maxillary sinuses are in the cheeks, the ethmoids are under the eyes, and the sphenoid sinuses are farther back in the head, near the pituitary gland. Paranasal sinuses are lined with mucous-producing epithelial tissue and have cilia to sweep mucous out of the sinuses and through the ostia into the nasal cavity.
Sinusitis is defined as an inflammation of the paranasal sinus lining commonly caused by bacterial, viral and/or microbial infections, as well as structural issues such as blockage of the sinus ostia. Symptoms include nasal congestion, facial discomfort, nasal discharge, headache, and fatigue. Sinusitis is considered acute when symptoms last 4 weeks or less. The disease is considered chronic when it lasts 3 months or longer. Sinusitis affects 37 million people each year, making it one of the most common health problems in the U.S. It is more prevalent than arthritis and hypertension and has a greater impact on quality of life than diabetes or congestive heart failure. Sinusitis is also responsible for $8 billion in direct healthcare expenditures and a significant loss of workplace productivity.
The initial therapy typically attempted when treating chronic sinusitis is drug therapy involving anti-inflammatory agents to reduce the inflammation and antibiotics to treat the infection. A large number of patients, however, do not respond to drug therapy and seek a surgical option. The most common surgical procedure currently performed for chronic sinusitis treatment is Functional Endoscopic Sinus Surgery (FESS).
In FESS, an endoscope is inserted into the nose and, under visualization through the endoscope, the surgeon removes diseased or hypertrophic bone and soft tissue in the nasal cavity and enlarges the ostia of the effected sinuses to restore normal drainage of the sinuses. Instruments used in FESS procedures are generally rigid surgical shavers, drills and burrs, and not only are the ostia enlarged during FESS procedures, but also anatomical structures are often removed just to gain access to the ostia with the rigid surgical tools. This removal of structures increases the post-surgical pain and bleeding after FESS. FESS procedures are typically performed with the patient under general anesthesia and involve days or even weeks of recovery, with painful and uncomfortable post-surgical packing of the nasal cavity, bleeding and scarring requiring follow-up debridement procedures.
Due to the invasiveness of FESS procedures, many otolaryngologists consider FESS an option only for patients who suffer from severe sinus disease (e.g., those showing significant abnormalities under CT scan), and many patients who would benefit from a surgical solution to their chronic sinusitis nevertheless avoid surgery. Thus, patients with less severe disease may not be considered candidates for FESS and may be left with no option but drug therapy.
An alternative to FESS employs dilating balloons and related devices for less invasive sinus intervention. Examples of dilating balloons and related devices and their methods of use can be found, for example, in U.S. patent application Ser. No. 10/829,917, entitled “Devices, Systems and Methods for Treatment of Nasal and Sinus Disorders of the Ears, Nose and/or Throat” and filed on Apr. 21, 2004; Ser. No. 10/944,270, entitled “Apparatus and Methods for Dilating and Modifying Ostia for Paranasal Sinuses and Other Intranasal or Paranasal Structures” and filed on Sep. 17, 2004; Ser. No. 11/037,548, entitled “Systems and Methods for Treating Disorders of the Ear, Nose and Throat” and filed on Jan. 18, 2005; and Ser. No. 11/150,847, entitled “Devices, Systems and Methods Useable for Treating Sinusitis” and filed: Jun. 10, 2005, which are incorporated by reference in their entirety. Less invasive procedures of the type described in the above applications may sometimes be referred to as “Balloon Sinuplasty™” or more generally “Sinuplasty.”
In addition to Balloon Sinuplasty™ devices, systems and methods, the assignee of the present invention has invented other devices, systems and methods for minimally invasive sinus procedures. For example, an irrigation catheter for use in the paranasal sinuses is described in U.S. patent application Ser. No. 12/011,100, entitled “Methods, Devices and Systems for Treatment and/or Diagnosis of Disorders of the Ear, Nose and Throat,” and filed on Jan. 23, 2008, the full disclosure of which is hereby incorporated by reference. Another example is a lighted guidewire device for use in a Balloon Sinuplasty™ procedure, such as the embodiments described in U.S. patent application Ser. No. 11/522,497, entitled “Methods and Devices for Facilitating Visualization in a Surgical Environment,” and filed Sep. 15, 2006, the full disclosure of which is hereby incorporated by reference.
In some Balloon Sinuplasty™ procedures, as well as in other procedures invented by the assignee of the present invention, such as paranasal sinus irrigation using an irrigation catheter device as described in the above-referenced patent application, a guidewire may be used for advancement and positioning of one or more devices in or through a paranasal sinus ostium and sometimes into a paranasal sinus itself. For example, in some procedures a guidewire may be advanced through an angled guide catheter, through a paranasal sinus ostium, and into a paranasal sinus. A balloon catheter may then be advanced over the guidewire to position a balloon of the catheter in the paranasal sinus ostium, and the balloon may then be inflated to expand the ostium. In some cases, the balloon catheter and guidewire may then be removed from the paranasal sinus by pulling them back through the angled guide catheter. Optionally, the same guide catheter, guidewire and balloon catheter may be used to access and expand multiple paranasal sinus ostia in one patient.
Although the assignee of the present invention has previously developed guidewires for use in such procedures, improvements are continually being sought. For example, when a distal end of a guidewire is passed into a sinus, it is often advantageous to continue to pass an additional length of guidewire into the sinus, thus causing it to curl and turn up on itself and thus facilitating confirmation of the location of the guidewire distal end in the sinus, using fluoroscopy. The distal end of the guidewire is also passed in and out of an angled guide catheter at least once and often more than once. These two parts of the procedure may often cause the guidewire to kink or bend, and this kinking or bending may make it very difficult or impossible to access subsequent paranasal sinuses in the same patient with the same guidewire. Ideally, the guidewire distal portion should be flexible enough to pass through tortuous anatomy without damaging the anatomy while also resistant to kinking and bending. The ideal guidewire should also be pushable, to allow it to be advanced through a guide catheter. Such a guidewire should also be sufficiently strong to support a balloon catheter, irrigation catheter or other device that is passed over it.
The challenges faced by a guidewire for paranasal sinus procedures are also much more daunting than those faced by a guidewire used in cardiology vascular applications. For example, the anatomy in the nasal cavity and paranasal sinuses is composed of bone covered in soft tissue, formed into many folds, twists and turns, so the sinus guidewire faces both hard tissue that it must navigate and soft tissue that it ideally will leave relatively undamaged. The circumference and shape of the paranasal sinus cavities vary significantly from patient to patient and within a patient. The circumference of a sinus cavity may vary from about 0.5 cm to about 10 cm within a patient. Based on the size of the sinus cavity, the amount of guidewire that is positioned in the sinus also can vary significantly. The amount of guidewire that is positioned in the sinus can also vary based on physician preference as well as support needed during passage of devices. The guidewire must also pass in and out of an angled guide catheter that is usually at least partially rigid while still retaining approximately it overall shape. Further, the guidewire must provide support for the balloon catheter, irrigation catheter or other device being advanced over it.
Thus, there is a need for devices and methods for easily navigating the complex anatomy of the nasal cavities and paranasal sinuses and for treating disorders of the paranasal sinuses with minimal complications due to individual variations in anatomy and causing minimal trauma to or disruption of anatomical structures that are not pathogenic. Specifically, there is a need for a guidewire that balances flexibility and ease of use with the resilience and rigidity to provide support for a balloon catheter, irrigation catheter and/or other device(s).